Characterization of novel antibodies that recognize sialylated keratan sulfate and lacto-N-fucopentaose I on human induced pluripotent cells: comparison with existing antibodies.

This report describes the isolation and characterization of two new antibodies, R-6C (IgM) and R-13E (IgM), which were generated in C57BL/6 mice (Mus musculus) using the Tic (JCRB1331) human induced pluripotent cell (hiPSC) line as an antigen, and their comparisons with two existing antibodies, R-10G (IgG1) and R-17F (IgG1). Their epitopes were studied by western blotting after various glycosidase digestions, binding analyses using enzyme-linked immunosorbent assays (ELISAs) and microarrays with various synthetic oligosaccharides. The minimum epitope structures identified were: Siaα2-3Galß1-3GlcNAc(6S)ß1-3Galß1-4GlcNAc(6S)ß1 (R-6C), Fucα1-2Galß1-3GlcNAcß1-3Galß1 (R-13E), Galß1-4GlcNAc(6S)ß1-3Galß1-4GlcNAc(6S)ß1 (R-10G), and Fucα1-2Galß1-3GlcNAß1-3Galß1-4Glc (lacto-N-fucopentaose I) (R-17F). Most glycoprotein epitopes are expressed as O-glycans. The common feature of these epitopes is the presence of an N-acetyllactosamine type 1 structure (Galß1-3GlcNAc) at their nonreducing termini, followed by a type 2 structure (Galß1-4GlcNAc); this arrangement comprises a type 1-type 2 motif. This motif is also shared by TRA-1-60, a traditional onco-fetal antigen. In contrast, the R-10G epitope has a type 2-type 2 motif. Among these antibodies, R-17F and R-13E exhibit cytotoxic activity toward hiPSCs. R-17F and R-13E exhibit extremely high similarity in the amino acid sequences in their complementarity-determining regions (CDRs), which is consistent with their highly similar glycan recognition. These antibodies are excellent tools for investigating the biological functions of glycoconjugates in hiPSCs/hESCs; they could be useful for the selection, isolation and selective killing of such undifferentiated pluripotent stem cells.

Evaluating distribution and variation of strains near eyes in blinking using digital image correlation.

BACKGROUND: Strain is occurred due to deformation such as the change of facial expression and is expected as a new evaluation approach to know the condition of skins applied to cosmetics. In this study, a noncontact in-site method by using digital image correlation for measuring the strain on the skin surface near the eyes where deformation always occurs by blinking is proposed. In this method, skin microrelief and irregularities are utilized for the measurement. MATERIALS AND METHODS: Images on the skin surface below the eyes of the four female subjects are pictured during a blink using high-speed cameras. The principal strains as well as the principal directions are obtained using digital image correlation. The reference updating algorism is used when the movement of the skin surface due to blink is large, and the eyelashes elimination algorism is used when the long eyelashes hide their skin surface in an image. The strain distributions in the local area below the right eye and the time histories of the strain near the eye under several skin conditions are evaluated for each subject. RESULTS: The strain can be obtained for each subject under each condition and the different strain distributions and time histories under different condition are visualized. CONCLUSION: The individual behavior of the subject and the different condition of the skin can be captured by the proposed method.

Clinical characteristics, treatment indications and treatment algorithm for post-partum hematomas.

AIM: Post-partum hematomas are a serious obstetrical complication. Choosing treatments for post-partum hematomas is difficult, and the application of transcatheter arterial embolization remains unclear. We aimed to clarify the clinical characteristics, identify the treatment indications and create a treatment algorithm for post-partum hematomas. METHODS: Fifty-four patients with post-partum hematomas were enrolled. Hematomas were categorized according to location: upper vaginal, lower vaginal and vulvar. Blood loss, treatment methods and other clinical data were collected from the patients' medical records and analyzed retrospectively. RESULTS: Five, 19 and 30 patients had upper vaginal wall, lower vaginal wall and vulvar hematomas, respectively. All upper vaginal wall hematomas required transcatheter arterial embolization to control bleeding, and the average blood loss was 2473 ± 1689 mL. Most lower vaginal wall hematomas were treated surgically; however, two patients required transcatheter arterial embolization, and the average blood loss in these patients was much higher (2010 ± 1145 mL) than that in patients with lower vaginal wall hematomas (395 ± 316 mL). No patient with vulvar hematomas was treated with transcatheter arterial embolization. Two and four patients with vulvar and lower vaginal wall hematomas, respectively, were managed with observation. CONCLUSION: We created an algorithm for post-partum hematoma management. Post-partum hematoma location should guide treatment selection. Transcatheter arterial embolization should be selected for upper vaginal wall hematomas. Most lower vaginal wall hematomas are treatable with surgery, but transcatheter arterial embolization should be considered for hemostasis in difficult cases. Management with observation may also be possible for lower vaginal wall and vulvar hematomas.

Laser Speckle Contrast Imaging for Intraoperative Quantitative Assessment of Intestinal Blood Perfusion During Colorectal Surgery: A Prospective Pilot Study.

BACKGROUND: The main limitation of perfusion assessment with indocyanine green fluorescence angiography during colorectal surgery is that the surgeon assesses the quality of perfusion subjectively. The ideal intestinal viability test must be minimally invasive, objective, and reproducible. We evaluated the quantitativity and reproducibility of laser speckle contrast imaging for perfusion assessment during colorectal surgery. METHODS: This was a prospective, nonrandomized, pilot study of 8 consecutive patients who underwent elective left-sided colorectal resection. Laser speckle perfusion images at the site of proximal transection of the bowel were obtained intraoperatively. We tested the hypothesis that laser speckle contrast imaging was able to quantitatively identify areas of diminished intestinal perfusion after devascularization and assessed the reproducibility of this method. RESULTS: All surgical procedures were uneventful and blood flow measurements were successfully made in all patients. None of the patients developed postoperative complications related to the anastomosis and stoma. Data analyses were successfully optimized to perform quantitative regional perfusion assessments in all cases. The bowel tissue blood flows of the anal side region adjacent to the transection line were significantly lower than those of the oral side region adjacent to the transection line after ligation of marginal vessels ( P = .012). Interrater reliability was high (intraclass correlation coefficients = 0.989), and a Bland-Altman plot showed few differences of mean flux data between 2 investigators. CONCLUSION: Laser speckle contrast imaging is feasible for real-time assessment of bowel perfusion with quantitativity and excellent reproducibility during colorectal surgery without administration of any contrast agents.

Podocalyxin as a major pluripotent marker and novel keratan sulfate proteoglycan in human embryonic and induced pluripotent stem cells.

Podocalyxin (PC) was first identified as a heavily sialylated transmembrane protein of glomerular podocytes. Recent studies suggest that PC is a remarkable glycoconjugate that acts as a universal glyco-carrier. The glycoforms of PC are responsible for multiple functions in normal tissue, human cancer cells, human embryonic stem cells (hESCs), and human induced pluripotent stem cells (hiPSCs). PC is employed as a major pluripotent marker of hESCs and hiPSCs. Among the general antibodies for human PC, TRA-1-60 and TRA-1-81 recognize the keratan sulfate (KS)-related structures. Therefore, It is worthwhile to summarize the outstanding chemical characteristic of PC, including the KS-related structures. Here, we review the glycoforms of PC and discuss the potential of PC as a novel KS proteoglycan in undifferentiated hESCs and hiPSCs.

Podocalyxin as a major pluripotent marker and novel keratan sulfate proteoglycan in human embryonic and induced pluripotent stem cells.

Podocalyxin (PC) was first identified as a heavily sialylated transmembrane protein of glomerular podocytes. Recent studies suggest that PC is a remarkable glycoconjugate that acts as a universal glyco-carrier. The glycoforms of PC are responsible for multiple functions in normal tissue, human cancer cells, human embryonic stem cells (hESCs), and human induced pluripotent stem cells (hiPSCs). PC is employed as a major pluripotent marker of hESCs and hiPSCs. Among the general antibodies for human PC, TRA-1-60 and TRA-1-81 recognize the keratan sulfate (KS)-related structures. Therefore, It is worthwhile to summarize the outstanding chemical characteristic of PC, including the KS-related structures. Here, we review the glycoforms of PC and discuss the potential of PC as a novel KS proteoglycan in undifferentiated hESCs and hiPSCs.

Binding specificity of R-10G and TRA-1-60/81, and substrate specificity of keratanase II studied with chemically synthesized oligosaccharides.

Recently, we established a mouse monoclonal antibody specific to hiPS/ hES cells, R-10G, which recognizes a type of keratan sulfate. Keratan sulfates (KS) comprise a family of glycosaminoglycans consisting of the repeating unit of [Gal-GlcNAc(6S)]. However, there is a diversity in the degree of sulfation at Gal and GlcNAc residues, and also in the mode of linkage, Galß1 - 3GlcNAc (type 1) or Galß1 - 4GlcNAc (type 2). To gain more insight into the binding specificity of R-10G, we carried out an ELISA test on avidin-coated plates using polyethylene glycol (PEG)3-biotinylated derivatives of a series of N-acetyllactosamine tetrasaccharides (keratan sulfates (KSs)). The results suggested that the minimum epitope structure is Galß1 - 4GlcNAc(6S)ß1 - 3Galß1 - 4GlcNAc(6S)ß1 (type 2- type 2 keratan sulfate). Removal of sulfate from GlcNAc(6S) or addition of sulfate to Gal abolished the binding activity almost completely. We also examined the binding specificity of TRA-1-60/81 in the same assay system. The minimum epitope structure was shown to be Galß1 - 3GlcNAcß1 - 3Galß1 - 4GlcNAcß1 in agreement with the previous study involving glycan arrays (Natunen et al., Glycobiology, 21, 1125-1130 (2011)). Interestingly, however, TRA-1-60/81 was shown to bind to Galß1 - 3GlcNAc(6S)ß1 - 3Galß1 - 4GlcNAc(6S)ß1 (type 1- type 2 keratan sulfate) dose-dependently, being more than one-third the binding activity toward Galß1 - 3GlcNAcß1 - 3Galß1 - 4GlcNAcß1 than in the case of TRA-1-60. In addition, a substrate specificity study on keratanase II revealed that keratanase II degraded not only "type 2-type 2 keratan sulfate" but also "type 1-type 2 keratan sulfate", significantly.

Characterization of glycoproteins expressing the blood group H type 1 epitope on human induced pluripotent stem (hiPS) cells.

Recently, we established two mouse monoclonal antibodies (R-10G and R-17F). The R-17F antibody (IgG1 subtype) exhibited a strong cytotoxic effect on hiPS/ES cells. The R-17F antigen isolated from a total lipid extract of hiPS (Tic) cells was identified as LNFP I (Fucα1-2Galß1-3GlcNAcß1-3Galß1-4Glc). In the present study, R-17F binding proteins were isolated from hiPS (Tic) cell lysates with an affinity column of R-17F. They gave one major R-17F positive band around 250 kDa, and several minor bands between 150 kDa and 25 kDa. The former band was identified as podocalyxin by LC/MS/MS after SDS-PAGE. Hapten inhibition studies on R-17F binding to R-17F column-purified proteins with various synthetic oligosaccharides revealed that the blood group H type 1 triaose structure (Fucα1-2Galß1-3GlcNAc) was the predominant epitope on all the R-17F binding proteins. These bands disappeared completely on digestion with α1-2 fucosidase, but not with α1-3/4 fucosidase. Upon PNGase F digestion, the R-17F positive band around and above 250 kDa did not show any change, while the minor bands between 150 kDa and 25 kDa disappeared completely, suggesting that the epitope is expressed on N-glycans in the latter and probably on O-glycans in the former. These results, together with those obtained in our previous studies on R-10G (Kawabe et al. Glycobiology, 23, 322-336 (2013)), indicated that both R-10G and R-17F epitopes are carried on the same podocalyxin molecule. The R-17F epitopes on these glycoproteins expressed on hiPS cells could be associated with the molecular mechanism underlying the carbohydrate-mediated cytotoxic activity of R-17F.

Involvement of STH7 in light-adapted development in Arabidopsis thaliana promoted by both strigolactone and karrikin.

Strigolactones (SLs) and karrikins (KARs) regulate photomorphogenesis. GR24, a synthetic SL and KAR1, a KAR, inhibit the hypocotyl elongation of Arabidopsis thaliana in a weak light. GR24 and KAR1 up-regulate the expression of STH7, encoding a transcription factor belonging to the double B-box zinc finger subfamily. In this study, we used STH7-overexpressing (STH7ox) lines and functionally defective STH7 (STH7-SRDX) mutants to investigate roles of SLs and KARs in photomorphogenesis of Arabidopsis. Hypocotyl elongation of STH7-SRDX mutants was less sensitive to both GR24 and KAR1 treatment than that of wild-type Arabidopsis under weak light conditions. Furthermore, the chlorophyll and anthocyanin content was increased in STH7ox lines when de-etiolated with light and GR24-treated plants had enhanced anthocyanin production. GR24 and KAR1 treatment significantly increased the expression level of photosynthesis-related genes LHCB1 and rbcS. The results strongly suggest that SL and KAR induce photomorphogenesis of Arabidopsis in an STH7-dependent manner.

Higher D-dimer level in the early third trimester predicts the occurrence of postpartum hemorrhage.

AIMS: This study aimed to determine effective predictive factors for primary postpartum hemorrhage (PPH) among clinical blood parameters associated with coagulation and fibrinolysis and demographic characteristics. METHODS: We retrospectively studied 1032 women who underwent determinations of clinical blood parameters at gestational week (GW) 29-32 and GW 35-37 and gave birth to singleton infants at our hospital between January 2011 and December 2013. PPH was defined as estimated blood loss ≥700 mL. Multivariate logistic regression analyses were used to determine independent risk factors and odds ratios (OR) for PPH. RESULTS: PPH occurred in 104 of 1032 women (10%). Three blood variables, fibrinogen level <4.0 g/L (OR [95% CI], 1.96 [1.18-3.27]), antithrombin activity <85% of normal activity level (1.84 [1.05-3.21]), and D-dimer level >2.7 µg/mL (2.03 [1.29-3.19]) at GW 35-37, and three demographic characteristics, maternal age ≥35 years (1.75 [1.15-2.68]), BMI >28.2 kg/m2 on admission for childbirth (1.95 [1.20-3.16]), and previous cesarean delivery (2.77 [1.31-5.83]), were identified as independent risk factors for PPH. CONCLUSION: Among blood parameters, higher D-dimer levels and lower levels of antithrombin activity and fibrinogen in late gestation were independent risk factors for PPH.

Reduced carotid baroreceptor distensibility-induced baroreflex resetting contributes to impairment of sodium regulation in rats fed a high-fat diet.

Decreased carotid arterial compliance has been reported in obese subjects and animals. Carotid baroreceptors are located at the bifurcation of the common carotid artery, and respond to distension of the arterial wall, suggesting that higher pressure is required to obtain the same distension in obese subjects and animals. A hyperosmotic NaCl solution induces circulatory volume expansion and arterial pressure (AP) increase, which reflexively augment renal excretion. Thus, we hypothesized that sodium regulation via the baroreflex might be impaired in response to chronic hyperosmotic NaCl infusion in rats fed a high-fat diet. To examine this hypothesis, we used rats fed a high-fat (Fat) or normal (NFD) diet, and measured mean AP, water and sodium balance, and renal function in response to chronic infusion of hyperosmotic NaCl solution via a venous catheter. Furthermore, we examined arterial baroreflex characteristics with static open-loop analysis and distensibility of the common carotid artery. Significant positive water and sodium balance was observed on the 1st day of 9% NaCl infusion; however, this disappeared by the 2nd day in Fat rats. Mean AP was significantly higher during 9% NaCl infusion in Fat rats compared with NFD rats. In the open-loop analysis of carotid sinus baroreflex, a rightward shift of the neural arc was observed in Fat rats compared with NFD rats. Furthermore, distensibility of the common carotid artery was significantly reduced in Fat rats. These results indicate that a reduced baroreceptor distensibility-induced rightward shift of the neural arc might contribute to impairment of sodium regulation in Fat rats.

Change in preference for vegetables and their perceptual attributes as a function of age and pickiness.

Preference for vegetables is influenced by various factors, including demographic, psychological, socio-environmental, and genetic factors. This study confirmed that age, pickiness, and perceptual attributes were predictors of preference for vegetables and examined how preference for vegetables and their perceptual attributes varies with age and pickiness. Children (8-14 years, n = 420), youth (15-34 years, n = 569), middle-aged adults (35-64 years, n = 726), and older adults (65-85 years, n = 270) were asked which vegetables they liked (or disliked) and which perceptual attributes of each vegetable they liked (or disliked). On the basis of their responses, an overall preference score and a preference sub-score for each perceptual attribute were calculated. Participants in each age group were classified into four statuses (non-, mild, moderate, and severe) according to their pickiness scores. Multiple regression analysis revealed that age and preference sub-scores for eight perceptual attributes (sweetness, sourness, bitterness, umami, pungency, orthonasal aroma, texture, and appearance) were positive predictors of overall preference score and that pickiness score and four perceptual attributes (saltiness, astringency, retronasal aroma, and aftertaste) were negative predictors. In addition, overall preference score and preference sub-scores for perceptual attributes other than saltiness increased with increasing age group and decreasing picker status; however, preference sub-scores for at least one of the six perceptual attributes (bitterness, astringency, pungency, orthonasal aroma, retronasal aroma, and aftertaste) exhibited negative values in children, youth, and pickers (mild, moderate, and severe). The increase in preference for these perceptual attributes might be an indicator of the adultization of food perception and the expansion of food acceptance.

Study of understanding the internalized stigma of schizophrenia in psychiatric nurses in Japan.

AIM: 'Internalized stigma' is a construct that reflects the degree to which a person accepts beliefs endorsed by society about mental illness. Among people with schizophrenia spectrum disorders, internalized stigma has been found to moderate the associations between insight and social function, hope, and self-esteem. Among families of patients with schizophrenia, internalized stigma may not only hinder help-seeking but also result in the families attempting to provide care themselves, without assistance from mental health services. Little is known about internalized stigma among service providers, especially psychiatric nurses in Japan. Therefore, we investigated the correlation between internalized stigma and 'beliefs about the most appropriate form of hospitalization' among psychiatric nurses. METHODS: The subjects were 215 psychiatric nurses employed in psychiatric hospitals who completed the personal stigma scale, perceived stigma scales, and Difficulty of Community Living Scale (DCLS) with respect to a chronic schizophrenia case vignette. RESULTS: Internalized stigma was positively correlated with greater 'beliefs about the most appropriate form of hospitalization' among psychiatric nurses. We also showed that stronger 'beliefs about the social disadvantages of schizophrenia patients in the community' was positively correlated with stronger 'beliefs about the most appropriate form of hospitalization'. CONCLUSION: The present findings suggest that the psychiatric nurses employed at Japanese psychiatric hospitals have a pessimistic view of the community living of people with schizophrenia and their families. And these psychiatric nurses' beliefs were related to their understanding of the deeply dependent relationship between patients and families, and was related to the Confucian ideal.

Nostalgia evocation through seasonality-conscious purchasing behavior revealed by online survey using vegetable names.

Food can be a valuable mediator of nostalgia. Japanese food culture places a great emphasis on seasons, and thus there may be a relationship between nostalgic foods and seasonality. In this study, we hypothesized that participants who emphasized seasonality at the time of vegetable purchase (seasonality-oriented; hereafter, SO) would be more likely to feel vegetable-evoked nostalgia than those who did not (non-seasonality-oriented; hereafter, non-SO). To test this hypothesis, we administered an online survey to older Japanese adults regarding 103 representative vegetables considered to be seasonal foods. After participants selected vegetables that they had eaten, they then selected those that evoked nostalgia (hereafter, nostalgic vegetables). For each nostalgic vegetable, they evaluated the degree of nostalgia and state if a past event (autobiographical memory) was recalled. If an autobiographical memory was recalled for a certain nostalgic vegetable, nostalgia for that memory was evaluated. Comparing between SO and non-SO participants, SO participants had significantly higher numbers of nostalgic vegetables with associated autobiographical memories, as well as nostalgia for those vegetables and autobiographical memories. The results supported our hypothesis, suggesting that seasonality-conscious purchasing behavior evokes nostalgia.

Glycan Epitopes on 201B7 Human-Induced Pluripotent Stem Cells Using R-10G and R-17F Marker Antibodies.

We developed two human-induced pluripotent stem cell (hiPSC)/human embryonic stem cell (hESC)-specific glycan-recognizing mouse antibodies, R-10G and R-17F, using the Tic (JCRB1331) hiPSC line as an antigen. R-10G recognizes a low-sulfate keratan sulfate, and R-17F recognizes lacto-N-fucopentaose-1. To evaluate the general characteristics of stem cell glycans, we investigated the hiPSC line 201B7 (HPS0063), a prototype iPSC line. Using an R-10G affinity column, an R-10G-binding protein was isolated from 201B7 cells. The protein yielded a single but very broad band from 480 to 1236 kDa by blue native gel electrophoresis. After trypsin digestion, the protein was identified as podocalyxin by liquid chromatography/mass spectrometry. According to Western blotting, the protein reacted with R-10G and R-17F. The R-10G-positive band was resistant to digestion with glycan-degrading enzymes, including peptide N-glycanase, but the intensity of the band was decreased significantly by digestion with keratanase, keratanase II, and endo-ß-galactosidase, suggesting the R-10G epitope to be a keratan sulfate. These results suggest that keratan sulfate-type epitopes are shared by hiPSCs. However, the keratan sulfate from 201B7 cells contained a polylactosamine disaccharide unit (Galß1-4GlcNAc) at a significant frequency, whereas that from Tic cells consisted mostly of keratan sulfate disaccharide units (Galß1-4GlcNAc(6S)). In addition, the abundance of the R-10G epitope was significantly lower in 201B7 cells than in Tic cells.

Electronic spectra of two long-lived photoproducts: double-proton transfer in 7-hydroxyquinoline dimer in a 2-methyltetrahydrofuran glass matrix.

Photoreactions of 7-hydroxyquinoline (7-HQ) in low-temperature (77-100 K) 2-methyltetrahydrofuran glass matrices are investigated using electronic spectroscopy. We have observed fluorescence excitation and fluorescence spectra of two long-lived species generated by irradiation of UV light (230-400 nm). The dominant species responsible for the fluorescence spectrum between 470 and 600 nm was assigned to the S(1)-->S(0) (pipi*) transition of the keto form of cyclic 7-HQ dimer [(7-HQ)(2)] produced by excited-state double-proton transfer, the corresponding S(1)-S(0) fluorescence excitation spectrum of which was detected between 360 and 510 nm. Temperature dependence of the fluorescence excitation spectra showed the occurrence of keto --> enol isomerization in the S(0) state of (7-HQ)(2) due to a back double-proton transfer. A very slow rate for the keto --> enol isomerization implies that the potential barrier height for the back double-proton transfer reacion is substantially high. Theoretical calculations at the MP2/aug-cc-pVDZ level of theory indicate that the enol and keto forms of cyclic (7-HQ)(2) are nonplanar, therefore a large change in the geometry is necessary for the back double-proton transfer. A second long-lived species that emits between 410 and 600 nm has been tentatively assigned to the D(3)(2A'') --> D(0)(1A'') transition of the 7-quinolinoxyl radical on the basis of calculated electronic transition energies for possible candidates obtained by MS-CASPT2/aug-cc-pVDZ level calculations as well as IR study of 7-HQ in argon matrices [Sekine, M.; Nagai, Y.; Sekiya, H.; Nakata, M. J. Phys. Chem. A 2009, 113, 8286]. Photoreaction processes leading to the two long-lived species have been discussed.

18F-sodium fluoride positron emission tomography may help determine better treatment for thigh pain after hip arthroplasty-A case report.

Thigh pain after hip arthroplasty is multifactorial; uncovering its etiology is paramount for optimal treatment. This is the first case where 18F-sodium fluoride positron emission tomography substantially helped in diagnosing the post-hip arthroplasty persistent thigh pain and appropriate treatment selection. This imaging modality warrants further study and more widespread application.

Photoinduced hydrogen-atom eliminations of 6-hydroxyquinoline and 7-hydroxyquinoline studied by low-temperature matrix-isolation infrared spectroscopy and density-functional-theory calculations.

Photoreaction mechanisms of 6-hydroxyquinoline (6-HQ) and 7-hydroxyquinoline (7-HQ) in low-temperature argon matrixes have been investigated by Fourier transform infrared (IR) spectroscopy and density-functional-theory (DFT) calculations. A comparison of the observed IR spectra of reactants with the corresponding calculated spectral patterns obtained by the DFT method led to the conclusion that the hydrogen atoms in the O-H group of 6-HQ and in that of 7-HQ are selectively located at the outer position against the quinoline ring. When the matrix samples were irradiated upon UV light around 300 nm, IR spectra of unknown chemical species were observed; they were assigned to the photoreaction intermediates, quinolinoxyl radicals and ketene compounds, produced by eliminations of a hydrogen atom and a hydrogen molecule, respectively. In the photoreaction of 7-HQ, a small amount of keto form was also produced by intramolecular hydrogen-atom transfer from oxygen to nitrogen in an argon cage. Kinetic analyses were made by assuming that 5-ketene and 6-ketene were produced from 6-HQ, while 6-ketene and 7-ketene were produced from 7-HQ. The effective rate constants estimated from the absorbance changes of IR bands against irradiation time revealed that the reaction pathway to produce 6-ketene was minor in both HQs, leading to the conclusion that the conformation of reactants, HQs, plays an important role in the photoproduction of ketenes through biradicals in the Wolff rearrangement.

Microdetermination of Sialic Acids in Blood Samples by Hydrophilic Interaction Chromatography Coupled to Post-column Derivatization and Fluorometric Detection.

An analytical method for the determination of sialic acids in biological samples has been developed and applied to fetal bovine serum (FBS), newborn calf serum and adult bovine serum. The hydrolysis of sera was carried out and the liberated sialic acids were quantified using a rapid and sensitive HPLC. The HPLC includes the separation and detection of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) using hydrophilic interaction liquid chromatography and a fluorometric post-column reaction with 2-cyanoacetamide. The calibration graphs for Neu5Ac and Neu5Gc were linear over the range of 10 pmol - 5 nmol. The concentrations of sialic acids in FBS, newborn calf serum and adult bovine serum were 5.06, 3.79 and 1.64 mM, respectively. The ratios of Neu5Gc and Neu5Ac changed dramatically according to the development stages. The present method has a satisfactory sensitivity in the quantification of Neu5Ac and Neu5Gc in serum samples. It seems that this analytical system can therefore be applied for routine use in clinical investigations of serum sialylation changes in cancer patients.